This section provides background information related to the present disclosure which is not necessarily prior art.
As the demand for electrical power increases during the day, the utility provider experiences an increase in the cost of generating electrical power as a result of secondary “peak” power plants that are switched on to supplement off-peak power generating plants. In situations where the peak demand begins to exceed the power generating capacity of the utility's off-peak and peak power plants, the utility may engage in demand side management, which curtails or reduces consumer energy usage to keep the demand from exceeding capacity. Utilities engaging in demand side management transmit a signal to various users of electrical energy to reduce the amount of energy they use during peak demand periods by turning off electrical loads such as air conditioners. In the example of an air conditioner controlled by a conventional thermostat, the utility provider may request reduced air conditioner operation by changing the set-point temperature of the thermostat. Previous attempts have been made to provide a load-shedding thermostat that can offset the temperature set-point to reduce the amount of energy used during peak demand periods. This would allow the utility to be able to lower energy consumption to keep the peak demand from exceeding their capacity, and the user would be able to save on their energy bill. However, this method of offsetting the temperature setting of a thermostat by a predetermined amount cannot always be relied upon to reduce the operating level of the air conditioner, since the user may respond to the displayed change in set-point temperature by over-riding the utility change to the set-point temperature setting.